Profile control and plug removal integrated operation system and method for polymer flooding and injection well

Abstract

The invention discloses a profile control and plug removal integrated operation system and method for a polymer flooding and injection well, and belongs to the technical field of profile control and plug removal of a polymer injection well in the petroleum drilling and production technology. The method comprises the following steps: manufacturing an artificial high-permeability core and a low-permeability core, evacuating saturated water and saturated oil from the high-permeability core and the low-permeability core, connecting the high-permeability core and the low-permeability core in parallel to form a model for simulating intra-layer and inter-layer heterogeneity of an oil reservoir, performing constant-speed water flooding, injecting a polymer solution into the parallel model at a constant speed, and performing subsequent water flooding until the water content is 90%; the calcium chloride, the spacer fluid and the sodium silicate solution are alternately injected into the parallel model for multiple rounds under constant pressure P profile control, and contact and react in the high-permeability layer to finally generate the silicate gel profile control agent; according to constant-pressure P plug removal, plug removal working liquid is injected into the parallel models, and the models are closed for 12-36 h; and injecting water into the parallel model under the constant-pressure P follow-up water drive, and performing follow-up water drive until the water content reaches 90%.

Description

technical field [0001] The invention belongs to the technical field of profile control and plug removal of polymer injection wells in oil drilling and production technology, and specifically relates to an integrated operation system and method for profile control and plug removal of polymer flooding and polymer injection wells. Background technique [0002] In recent years, with the rapid development of the national economy, my country's demand for oil has greatly increased, and the demand for enhanced oil recovery technology in major oil fields is increasing. [0003] In my country, most of the oil reservoirs are continental deposits, and their reservoirs are highly heterogeneous. In the process of water flooding development, the injected water will preferentially enter into places with lower seepage resistance (ie, the starting pressure of liquid absorption). High permeability layer, resulting in increased crude oil recovery and reduced seepage resistance. On the one hand,...

AI Technical Summary

Problems solved by technology

At present, the injection method of plugging removal working fluid in mines is usually general injection, and the actual plugging removal effect is poor. According to the analysis, due to the difference in hydraulic pressure absorption of high permeability layers, that is, the liquid absorption capacity is much greater than that of medium and low permeability layers, and the total volume of plugging removal working fluid less (100m 3 ~300m 3 ) and fast injection speed (0.5m 3 / min~1.5m 3 / min), the total construction time is relatively short, so the medium and low permeability layer sucks a small amount of working fluid for plugging removal, which is the fundamental reason for the poor plugging removal effect.

In order to increase the inhalation of working fluid for plugging removal in middle and low permeability layers, the mine also tried profile control first to increase the seepage resistance of high permeability layers, followed by plugging removal injection, and the profile control agents used were mostly polymer gels. However, this Profile control agents have the disadvantages of high viscosity (generally greater than 100mPa·s), poor injectability, etc. During mine construction, the injection pressure will increase significantly, and the profile control agent will inevitably enter the middle and low permeability layer, causing secondary damage

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